10_tm2100eu03tm_0001_exercises

Exercises Siemens

TM2100EU03TM_0001 © 2001 Siemens AG

1

Contents

1 Exercises 3

2 Solution 29

Exercises

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

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Exercises Siemens


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1 Exercises

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

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Exercises Siemens


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Exercise 1

Title: Introduction

Objectives: The participant is able to explain the most important steps of the GSM evolution

Pre-requisite: None

Task

Please answer the following questions.

Query

1. What were the requirements when designing the GSM specifications?

2. What does duplex connection mean?

3. What are the main advantages of GSM?

4. What were the problems of single cell systems?

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

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5. How is it possible to avoid interference in cellular systems?

6. When did the work on the GSM standardization start and when did the first commercial network start operation?

7. Which features are used to characterize an electromagnetic wave?

8. Which of the following services were implemented in GSM phase 2? And what does these abbreviations stand for

��HR

��FR

��ASCI

��EDGE

��MtP

��EFR

9. How many traffic channels are offered in GSM 1800?

��124

��374

��174

��299

Exercises Siemens


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10. What kinds of advantages does UMTS offer?

��better coverage

��world wide access

��high data rates

��flexible data rates

11. What are the advantages the digital technology used in GSM?

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

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Exercises Siemens


9

Exercise 2

Title: Transmission Principle

Objectives: The participant is able to explain the basic transmission principles

Pre-requisite: None

Task


Query

1. What is a duplex distance?

2. Which different kinds of fixed networks do we have?

3. Which elements are needed in a PLMN?

4. Transmission problems like multipath propagation are very common. What are the reasons for multipath propagation and how can the network compensate for these interferences?

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

10

5. Frequency hopping does what?

6. Why is it possible to archive full coverage of a country with a cellular network?

7. What is a cluster?

8. What does handover mean?

9. Why do we need locations areas / location update procedures?

10. How can we organize the multiple access?

Exercises Siemens


11

11. Frequency resources are limited. In which way are the resources best used?

12. What does roaming mean?

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

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Exercises Siemens


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Exercise 3

Title: GSM services

Objectives: The participant is able to explain the services offered in GSM

Pre-requisite: None

Task


Query

1. How many time slots can be theoretically / really be used in HSCSD?

2. What are the advantages of GSM?

3. What are the main new features of EDGE?

4. How high is the theoretical data rate you can transport in one time slot in GPRS?

��9.6 kbits/s

��9.05 kbit/s

��13.4 kbit/s

��14.4kbit/s

��15.6 kbit/s

��21.4 kbit/s

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TM2100EU03TM_0001

© 2001 Siemens AG

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5. What are the advantages of ASCI?

6. What is the advantage of Intelligent Network for the operator and for the user?

7. Please give two examples of supplementary services:

Exercises Siemens


15

Exercise 4

Title: GSM-PLMN

Objectives: The participant is able to explain the GSM-PLMN

Pre-requisite: None

Task

Please answer the following questions below

Query

1. The subsystems of a GSM network are:

��OSS

��PSTN

��MS

��BSS

��NSS

��ISDN

2. Which are the components of the NSS?

3. Which are the tasks the BSS is responsible for?

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TM2100EU03TM_0001

© 2001 Siemens AG

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4. To which part of the network does the TRAU belong? Where is it normally implemented and why?

5. Which two new Hardware elements are implemented in the NSS for implementing GPRS?

��SGSN

��CSE

��GMSC

��VLR

�� GGSN

6. The task of the TRAU is speech compression. Why has speech to be compressed? How are the compressed data transported in the time slots on the BSS side ?

7. What does channel coding mean?

Exercises Siemens


17

Exercise 5

Title: Procedures

Objectives: The participant is able to understand the common procedures of GSM

Pre-requisite: None

Task


Query

1. What is the format of the 1) IMSI 2) MSRN 3) LAI

��MCC + NDC + LAC

��MCC + MNC + SN

��CC + MNC + SN

��CC + MNC + LAC

��MCC + MNC + LAC + CI

2. What are the security features used in GSM?

3. What is the content of a triple?

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

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4. Can you explain how SRES /Kc are generated?

5. What are SRES and Kc used for?

6. Complete the following:

text: 1 0 0 1 1 1 0 0 1

ciphered sequence: 1 1 x 0 x 1 1 x x

ciphered text: x x 0 x 0 x x 1 1

7. When is a new TMSI allocated to a mobile user?

8. Who initiates the location update procedure?

9. Which different types of LU do you know?

Exercises Siemens


19

10. Do you know one situation where no LU is needed although the LA is changed?

11. If the timer for periodic LU is set to 60 min. a LU is needed:

��60 min after the last periodic LU

��60 min after the last power on LU

��60 min after the last generic LU

��60 min after the last transaction of any kind with the NSS

12. In an Inter VLR-LU, the new VLR asks the old VLR for information. Which information is provided by the old VLR?

��IMSI + triples

��IMSI + TIMSI + sub-services

��IMSI + last LU

��IMSI + HLR-address

13. When is the traffic channel reserved for a MTC?

��Subscriber B answers the ringing of the phone

��the MSRN is analyzed and the LA of B is known

��the MS of subscriber B answer the paging signal

14. What is different for an OACSU in comparison to a MOC?

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

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15. Which HO-types do you know?

16. When do we use an Intra-Cell HO?

17. What is different for an emergency call in comparison to a MOC?

Exercises Siemens


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Exercise 6

Title: Protocols

Objectives: The participant is able to understand the common protocols of GSM

Pre-requisite: None

Task

Please answer the following questions?

Query

1. Why do we need signaling?

2. What are typical signaling procedures? Give three examples.

3. Which SS7 protocols do not exist in a PSTN exchange?

��MTP

��SCCP

��ISUP

��TCAP

��MAP

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

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4. Which GSM network elements do not have SS7

5. What are the different tasks of the two BSSAP sub layers?

6. The LAPD-protocol has the same functionality as the

��SCCP

��network layer

��data link layer

��ISUP

Exercises Siemens


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Exercise 7

Title: Radio Interface

Objectives: The participant is able to understand radio interface of GSM

Pre-requisite: None

Task


Query

1. What is a burst?

��content of a TDMA frame?

��content of a TS

��pulse operation

��transmission operation

2. How many bits are transmitted in a burst?

��142 bits

��114 bits

��156.25 bits

��57 bits

3. Which modulation scheme is used in GSM?

��Phase modulation

��Amplitude modulation

��Frequency modulation

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

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4. Frequency hopping means periodic change of the:

��TS

��carrier

��TS + carrier

5. Why is Timing Advance needed in GSM?

6. The signaling multi-frame consist of

��51 TDMA-frames



��8 TS

7. Hyper-frames are used for:

��ciphering

��FH

��allocation of signaling data

��allocation of traffic data

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8. Which of the following channels are dedicated channels?

��FCCH

��SCH

��AGCH

��SACCH

��BCCH

��SDCCH

��TCH

��FACCH

9. What is transmitted in an AGCH?

��Frequency hopping. scheme

��Handover-Information

��gives dedicated signaling control channel to a user

��TA-Information

10. What type of logical channel is used for transmitting SMS in GSM?

��SDCCH

��SACCH

��TCH

��FACCH

11. Which channels is used for giving frequency-hopping information to a mobile user?

��BCCH

��FCCH

��RACH

��AGCH

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

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12. Which 51-multiframe combination can be used alone?

��IV

��V

��VI

��VII

Exercises Siemens


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Exercise 8

Title: Siemens Solution

Objectives: The participant has an overview to the Siemens Solution

Pre-requisite: None

Task


Query

1. Which different types of BTSE do you know?

2. How many TRXs can you put in one cell using the BTSE-24-familie?

3. Which different modules do you find in the BS 240?

4. Which different types of antennas can be used in Siemens solution?

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

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5. Which different BSC-BTS configurations do you know?

6. What does the SSS consist of?

7. How many LTGs can be connected to one SN B?

Exercises Siemens


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2 Solution

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

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Exercises Siemens


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Solution 1

Title: Introduction

Objectives: The participant is able to explain the most important steps of the GSM evolution.

Pre-requisite: none

Task


Query

1. What were the requirements when designing the GSM specifications?

had to be compatible with existing standards / standardized globally / built without causing major changes to the PLMN

2. What does duplex connection mean?

Two-way communication

3. What are the main advantages of GSM?

international roaming / more security /

4. What were the problems of single cell systems?

no handover / no roaming / bad quality

5. How is it possible to avoid interference in cellular systems?

each cells use different carriers / frequency reuse distance

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

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6. When did the work on the GSM standardization start and when did the first commercial network start operation?

start 1978, commercial start 1992

7. Which features are used to characterize an electromagnetic wave?

phase, frequency, amplitude

8. Which of the following services were implemented in GSM phase 2? And what does these abbreviations stand for

��HR

��FR

��ASCI

��EDGE

��MtP

��EFR

9. How many traffic channels are offered in GSM 1800?

��124

��374

��174

��299

10. What kinds of advantages does UMTS offer?

��better coverage

��world wide access

��high data rates

��flexible data rates

Exercises Siemens


33

11. What are the advantages the digital technology used in GSM?

higher security, transmission quality, network capacity, miniaturization

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

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Exercises Siemens


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Solution 2

Title: Transmission principle


Pre-requisite: none

Task


Query

1. What is a duplex distance?

distance between uplink –downlink, 45 MHz

2. Which different kinds of fixed networks do we have?

PSTN, ISDN, PDN

3. Which elements are needed in a PLMN?

mobile component - mobile station;

fixed network component - BSS and NSS

4. Transmission problems like multipath propagation are very common. What are the reasons for multipath propagation and how can the network compensate for this interference?

reflection of electromagnetic waves

interleaving, redundancy, antenna diversity, frequency hopping, power control

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

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5. Frequency hopping does what?

eliminate the problems of fading dips, interference

6. Why is it possible to archive full coverage of a country with a cellular network?

one cell can be put directly beside another cell

7. What is a cluster?

smallest domain within which all frequencies are used

8. What does handover mean?

changing cells during a connection

9. Why do we need locations areas / location update procedures?

to give the network the information about the location of the MS

10. How can we organize the multiple access?

FDMA, TDMA, CDMA

11. Frequency resources are limited. In which way are the resources best used in GSM?

Using both, FDMA and TDMA principle; possibility of Half Rate Speech, compression of speech data

Exercises Siemens


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12. What does roaming mean?

subscriber can move freely within the PLMN and remain reachable

Exercises Siemens


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Solution 3

Title: GSM services


Pre-requisite: none

Task

Please answer the following questions

Query

1. How many time slots can be theoretically / really be used in HSCSD?

in theory: 8 TS

in practice: 3TS ( in the moment)

2. What are the advantages of GSM?

international roaming / higher security

3. What are the main new features of EDGE?

new modulation scheme 8 PSK

4. How high is the theoretical data rate you can transport in one time slot in GPRS?

��9.6 kbits/s

��9.05 kbit/s

��13.4 kbit/s

��14.4kbit/s

��15.6 kbit/s

��21.4 kbit/s

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

40

5. What are the advantages of ASCI?

group and broadcast services with a fast call setup and control of priority

6. What is the advantage of Intelligent Network for the operator and for the user?

operator can rapidly adapt to changing market demands for new services

user can implement easier more flexible services, improve user to control over their services

7. Please give two examples of supplementary services:

sea page 11 (Chapter 3)

Exercises Siemens


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Solution 4

Title: GSM-PLMN

Objectives: The participant is able to explain the GSM PLMN

Pre-requisite: none

Task

Please answer the following questions

Query

1. The subsystems of a GSM network are:

��OSS

��PSTN

��MS

��BSS

��NSS

��ISDN

2. Which are the components of the NSS?

MSC / HLR / AC / VLR / EIR

3. Which are the tasks the BSS is responsible for?

radio network control, BSS control, database storage of BSS

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

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4. To which part of the network does the TRAU belong? Where is it normally implemented and why?

belong to BSS

normally implemented beside MSC, save costs for lines

5. Which two new Hardware elements are implemented in the NSS for implementing GPRS?

��SGSN

��CSE

��GMSC

��VLR

�� GGSN

6. The task of the TRAU is speech compression. Why has speech to be compressed? How are the compressed data transported in the time slots on the BSS side ?

to get higher capacity on the air interface, on the air interface in one time slot only 13 kbit/s can be transmitted

transported in sub-time slots of 16 kbit/s

7. What does channel coding mean?

Exercises Siemens


43

Solution 5

Title: Procedures

Objectives: The participant is able to understand common procedures of GSM

Pre-requisite: none

Task


Query

1. What is the format of the 1) IMSI 2) MSRN 3) LAI

��MCC + NDC + LAC (LAI)

��MCC + MNC + MSId (IMSI)

��CC + MNC + SN (MSRN)

��CC + MNC + LAC

��MCC + MNC + LAC + CI

2. What are the security features used in GSM?

authentication / ciphering / TMSI allocation / IMEI check

3. What is the content of a triple?

RAND / SRES / Kc

4. Can you explain how SRES /Kc are generated?

SRES: (RAND + Ki) * A3

Kc: (RAND + Ki) * A8

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

44

5. What are SRES and Kc used for?

SRES: authentication

Kc: ciphering

6. Complete the following:

text: 1 0 0 1 1 1 0 0 1

ciphered sequence: 1 1 0 0 1 1 1 1 0

ciphered text: 0 1 0 1 0 0 1 1 1

7. When is a new TMSI allocated to a mobile user?

whenever the TMSI is sent unciphered over the air interface

8. Who initiates the location update procedure?

Mobile Station

9. Which different types of LU do you know?

normal / periodic / with IMSI attach

10. Do you know one situation where no LU is needed although the LA is changed?

in case of a connection

Exercises Siemens


45

11. If the timer for periodic LU is set to 60 min. a LU is needed:

��60 min after the last periodic LU

��60 min after the last power on LU

��60 min after the last generic LU

��60 min after the last transaction of any kind with the NS

12. In an Inter VLR-LU, the new VLR asks the old VLR for information. Which information is provided by the old VLR?

��IMSI + triples

��IMSI + TIMSI + sub-services

��IMSI + last LU

��IMSI + HLR-address

13. When is the traffic channel reserved for a MTC?

��Subscriber B answers the ringing of the phone

��the MSRN is analyzed and the LA of B is known

��the MS of subscriber B answer the paging signal

14. What is different for an OACSU in comparison to a MOC?

no traffic channels assignment until B-subscriber answer

15. Which Handover-types do you know?

intra cell HO / intra BSC HO / inter BSC HO / inter MSC HO

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

46

16. When do we use an Intra-Cell HO?

in case of interference on one carrier if there is no frequency hopping

17. What is different for an emergency call in comparison to a MOC?

without authentication, ciphering, IMEI check, TMSI reallocation

without needing a SIM card

Exercises Siemens


47

Solution 6

Title: Protocols

Objectives: The participant is able to understand the common protocols of GSM

Pre-requisite: none

Task

Please answer the questions.

Query

1. Why do we need signaling?

for information exchange between network elements

2. What are typical signaling procedures? Give three examples.

Location Update, Mobile Origination Call, Authentication, …

3. Which SS7 protocols do not exist in a PSTN exchange?

��MTP

��SCCP

��ISUP

��TCAP

��MAP

4. Which GSM network elements do not have SS7

BSC – MSC / NSS / MSC – ISDN, PSTN

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

48

5. What are the different tasks of the two BSSAP sub layers?

BSSMAP / DTAP

6. The LAPD-protocol has the same functionality as the

��SCCP

��network layer

��data link layer

��ISUP

Exercises Siemens


49

Solution 7

Title: Radio Interface

Objectives: The participant is able to understand the GSM radio interface

Pre-requisite: none

Task


Query

1. What is a burst?

��content of a TDMA frame?

��content of a TS

��pulse operation

��transmission operation

2. How many bits are transmitted in a burst?

��142 bits

��114 bits

��156.25 bits

��57 bits

3. Which modulation scheme is used in GSM?

��Phase modulation

��Amplitude modulation

��Frequency modulation

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

50

4. Frequency hopping means periodic change of the:

��TS

��carrier

��TS + carrier

5. Why is Timing Advance needed in GSM?

compensation of propagation delay

6. The signaling multiframe consist of




��8 TS

7. Hyper-frames are used for:

��ciphering

��FH

��allocation of signaling data

��allocation of traffic data

Exercises Siemens


51

8. Which of the following channels are dedicated channels?

��FCCH

��SCH

��AGCH

��SACCH

��BCCH

��SDCCH

��TCH

��FACCH

9. What is transmitted in an AGCH?

��Frequency hopping scheme

��Handover-Information

��gives dedicated signaling control channel to a user

��TA-Information

10. What type of logical channel is used for transmitting SMS in GSM?

��SDCCH

��SACCH

��TCH

��FACCH

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

52

11. Which channels is used for giving frequency-hopping information to a mobile user?

��BCCH

��FCCH

��RACH

��AGCH

12. Which 51-multiframe combination can be used alone?

��IV

��V

��VI

��VII

Exercises Siemens


53

Solution 8

Title: Siemens Solution

Objectives: The participant has an overview of the Siemens solution

Pre-requisite: none

Task


Query

1. Which different types of BTSE do you know?

BTSE 11 / 20,21,22 / 40,41 / 60,61 / 82 / 240, 241, 242

2. How many TRXs can you put in one cell using the BTSE-24-familie?

12

3. Which different modules do you find in the BS 240?

Core Modules: COBA, COSA / Carrier Unit / Antenna Combiner / Multi Coppler / Alarm Collector Terminal

4. Which different types of antennas can be used in Siemens solution?

One Duplex Amplifier Multi Coupler (DUAMCO) or Filter Combiner (FICOM) + Di Amplifier Multi Coupler (DIAMCO)

5. Which different BSC-BTS configurations do you know?

star / loop / multidrop chain

Siemens Exercises

TM2100EU03TM_0001

© 2001 Siemens AG

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6. What does the SSS consist of?

LTG / SN 7 DSU / SSNC / CA

7. How many LTGs can be connected to one SN B?

64 / 128 / 256 / 512

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